Radio reception



Dec. 4, 1934;

w. J SCHNELL RADIO RECEPTION Fi led June 22, 1933 Patented Dec. 4, 19341,982,965 RADIO RECEPTION William J. Schnell, Berwyn, Ill., assignor toElectrical Research Laboratories, Inc., Chicago, 111.;- a corporation ofIllinois Application June 22, 1933, Serial-No. 676,997

Claims. (01. 250-20) This invention has to' do with a radio receiverhaving a local and remote loud speaker generally of the electrodynamictype, and relates particularly to an operating means for 5 completelydeenergizing one of said speakers concurrently with the energization ofthe other.

The primary object of the present invention is to provide, for use witha portable radio set and particularly with the so-called midget sets, anauxiliary loudspeaker of greater size than that contained in the midgetreceiving set and remote from said set but which will be energizedconcurrently with de-energization of the speaker in the set, the volumeand reproduction of such remote loud speaker being regulated from thedial and other controls upon the receiving set.

It is a further object of thepresent invention to provide a novelelectric circuit whereby an electrodynamic loud speaker may beconvenient- I 13'; operated remotely to a receiving set proper andcontrolled from said set as simply and satisfactorily, mechanically, asa speaker forming an integral part of such set Another object of thepresent invention is the provision of an improved control circuit foroperating an electrodynamic speaker remotely of a radio receiving setand" whereby a speaker forming a part of the receiving set proper may beused alternately but not concurrently there-v with.

Another object of the present invention is the provision, in' connectionwith a radio receiver having anelectrodynamic loud speaker, of a newcontrol circuit for operating a remote electrodynamic speaker and forthe independent operation of such speakers.

' Another object of the present invention is the provision of animproved circuit for controlling an electrodynamic loud speaker at adistance i from a radio receiver, the circuit employing .the

plate current of a thermionic tube of the'receiver for controlling theexcitation of the field coil of the distant speaker.

Still another object of the present invention is toprovide; incombination with a radio receiver operating in conjunction with a remoteloud speaker of the electrodynamic type, a multiple conductor cable forsupplying energy to the receiver from a source near the remote speaker.

Still another object of the present invention is to provide, in amultiple conductor cable extending between a radio receiver and a loudspeaker placed remotely thereof, a conductor suitable for use as anantenna for the receiver.

With the above and other desirable objects in view, the novelarrangement, improved combination and unique construction of the partscomprising a single form of the invention which will be hereinafterdescribed inconjunction with the accompanying single'sheet of drawingshere: by made a part of this specification, and in which:

Figure 1' is a digrammatic.representation of one form of the inventionshowing the manner of its installation'in relation to a radioreceiver;and

Figure 2 is a fragmentary view of. a multiple conductor cable andconnecting means, thereon comprising a part of. the device illustratedin the preceding figure.

Like reference characters willbe used. in the several figures of thedrawing .and throughout the following description for designatingsimilar parts of the'illustrated device. 7

Reference will first be had to Figure '1,.in which the dotted line 10 isrepresentative ofa cabinet for enclosing the main parts of a radioreceiving set. The invention is notlimited in its application to anyparticular type of radio re-.

ceiver. For that reason, many parts are omitted irom'thediagram oi. thereceiver. illustrated in Figure 1. Only those parts necessary to theoperation of the present invention and which are conventional parts ofany radio receiver employing'vacuum tubes are." shown.

The reference character '11 designates a compact antenna unit, which maybe transported together with the main part of the receiver indicated bythe ordinal12.. Condensers 13 and 14 and a transformer 15 are connectedto the antenna 11 in a customary manner. .A conductor 16 leads fromantenna 11 to a jack-receptacle 1'7. Within the main part of thereceiver 122 is an electro-dynamic speaker 18 comprising a voice coil 19and a field coil 20. The output tube 21 contains aplate 22, a filament23 and other conventional elements. The invention is equally applicablefor use with a receiver employing simple triodes having but a filament,a grid and a plate. Power may be conducted to the main part of thereceiver through a twisted pair 24,- which leads to a unit 25 forproviding B battery energy for the receiver. Circuit legs 26 and '27extend from the terminals of the conductor cord 24 to conduct energy tothe tube filaments within the receiver. If desired, the unit 25 may bereplaced by a group of dry cells.

A circuit designated generallyby the numeral 28 leads from the, source25 of B energy cur.

through the field coil 20 of the speaker 18, terminals 29 and 30 of aswitch 31 when the switch blade '75 is thrown to the left and back tothe source of 13 energy. A second circuit 32 leads from the plate 22 ofthe vacuum tube, through terminals 33 and 34 of switch 31, when theswitch blade 35 is thrown to the left, through the primary of atransformer 36 to the positive terminal of the source 25 of B energy.Transformer 36 transforms the potential of the energy impressed acrossits primary coil to the proper potential to be impressed onto the voicecoil 19 of the speaker 18. v v 7 At the right side of Figure 1 is acabinet 40 represented by dotted outline. Cabinet 40 is suitable forhousing an electrodynamic' speaker 41 comprising a voice coil 42 and afield coil 43. A small transformer 44 similar to transformer 36 is incircuit with the voice coil 42. A circuit for conducting electricalenergy to the field coil 43 includes a twisted pair 45 which mayterminate in an outlet plug 46, a relay 4'? comprising a magnetic coil48 and a switch 49, a transformer 50 and a current rectifier 51. Ifpreferred, dry cells may be employed in place of the rectifier 51.

The coil 48 of the relay 4'7 is connected in series with a circuitleadingfrom the plate 22 of vacuum tube 21 through terminals 33 and 52of switch 31, when the switch blade 35 is thrown to the right, through ajack consisting of a plug 53 and a receptacle 54, conductor 55 in themultiple conductor cable 55a, through the terminal 56 in terminal block5'7 and the corresponding terminal connector 58 in terminal block 59,through the primary of transformer 44, through the parallel arrangementof the coil 48 and condenser 59a, through complemental terminals 60 and61 in the terminal blocks 59 and 5'7, through conductor 62 in themultiple conductor cable 55a, through jack plug 63 and receptacle 64therefor and thence .to the positive terminal of the source 25 ofB'energy.

Conductors 64 and 65 of the cable 55:: lead from terminals 66 and 6'7 interminal block 57 to a side outlet 68 of the cable. Outlet 68 may beconnectedwith the fixture 69 at the; end of the twisted pair...24.Terminals 66 and 6'? automatically connect, respectively, "with terminals '70 and '71 within terminal block 59 when the two blocks'5'7 and 59are placed together.

Afifth conductor 72, in the cable 55a is illustrated as being free ofthe terminal members in the terminal block 57. Conductor 72 is suitedfor use as an antenna in conjunction with the antenna 11, and has a jackplug '73 attached to an endthereof for engaging the jack-receptacle In'the description of the operation of the device, it will be assumed thatthe main part 12 of the set is energized in some such manner as byinserting a terminal'plug (not shown) into a suitable wall outlet or thelike,,to connect with a source of electrical energy. Jack plugs '13, 63and 53 will be inserted into their respective receptacles. The plug 69will be inserted into receptacle 68. The switch blades 35 and '75, whichare mechanically interlocked, are moved to the left to make connectionwith the switch points 30and 34. When the switch blades are thrown tothe left, the field coil 20 of speaker 18 and the voice coil 19 thereofwill be supplied with energy from the source 25 of B energy and from theplate of the output tube respectively, and the speaker" 18 will beproperly energized for operation. When, however, the switch blades ofswitch 31 are thrown to the right, the circuit to the field coil 20 willbe opened as will the circuit for conducting energy from the plate 22 tothe voice coil 19.

The switch blade '75, when thrown to the right, will be dead ended atthe switch point 76. At the same time, the blade 35 will complete acircuit between switch points 33 and 52. Incidental to switch blades 35and '75 being thrown to the right, a path for energy will be traced fromplate 22 through switch points 33 and 52, jack parts 54 and 53, theconductor 55, terminals 56 and 58, the primary of transformer 44, theelectro-magnetic' coil 48, terminals 60 and 61, conductor 62, jack parts63 and 64 and to the positive terminal of the B source of energy. Theamount of direct current through the plate circuit just described issufiicient to actuate the relay 47 to close switch 49 whereby the fieldcoil 43 of the speaker 41 is energized.

The condenser 59a serves as a by-pass about the coil 48 to permit theimpulses of energy of audio frequency to pass to the voice coil 42 ofspeaker 41. By throwing the blades of switch 31 in one direction one ofthe electro-dynamic speakers may be wholly de-energized and the otherenergized, and by throwing the blades of said switch 31 in the oppositedirection, the energization and de-energization of the speakers will bereversed.

Hereinabove it is mentioned that the conductors 26 and 2'7 are energizedfrom a source of electrical energy not shown. Hence energy for the fieldcoil of the speaker 41, when switch 49 is closed, may be conducted fromsuch undisclosed energy source by way of conductors 26 and 2'7, thetwisted pair 24, conductors 64 and 65, and the circuit within thecabinet 40 including the relay switch 49, the transformer 50 and therectifier 51.

If it happens that the main part 12 of the receiver set is small enoughto be portable, such part of the receiver may be transported by placingthe, plug 46 into a suitable wall outlet and by disconnecting theheretofore mentioned attachment for supplying energy to the part 12. Thepart 12 of the receiver may then be transported pursuant to receivingenergy by way of the twisted pair 45, conductors 64 and 65 and thetwisted pair 24. That is, if it is desired to move the cabinet ;10 to amore suitable position where there may be no source of energy for theregular means (not shown) for tapping energy, the plug 46 may beconnected to a source of energy whereby the parts within the cabinet 10may receive energy by way of the multiple conductor 55a. I

When the receiver 12 has energy conducted thereto by way of the twistedpair 24, the switch 24a may be used for turning off and on, :the energy.

What is claimed as new and is desired to be secured by Letters Patent ofthe United States is:

1. In combination, a radio receiving set and a case therefor having abuilt-in dynamic loud speaker with voice and field coils, a seconddynamic loud speaker with voice and field coils remote from saidreceiving set, a first circuit between said receiving set and saidbuilt-in loud speaker, a second circuit between said receiving set andsaid remote loud speaker, a unitary switch for selectively impressingthe output of said receiving set upon the voice coils of said speakersby means of said circuits, a third circuit for impressing electricalenergy upon the field coil of said remote loud speaker; a relaycomprising a switch in said third circuit for the closing thereof, andelectromagnetic means in said second circuit for actuating said relayswitch, said electromagnetic means being energized incident to. theimpression of such output upon the voice coil of said remoteloud-speaker. .2. In combination, a radio receiving set and a casetherefor having a built-in dynamic loud speaker with voice and fieldcoils, a second dynamic loud speaker with voice and field coils remotefrom said receivingset, a cable having conductors therein and extendingbetween said receiving set and said remote loud speaker, a first circuitbetween said receiving set and said builtin loud speaker, a secondcircuit between said receiving set and said remote loud speaker andcomprising conductors in said cable, a unitary switch for selectivelyimpressing the output of said. receiving set upon the voice coils ofsaid speakers by means of said circuits, a third circuit for impressingelectrical energy upon the field coil of said remote loud speaker, arelay comprising a switch in said third circuit for the closing thereof,and electro-magnetic means in said second circuit for actuating saidrelay switch, said electromagnetic means being energized incident to theimpression of such output upon the voice coil of said remote loudspeaker. 3:. In combination, a radio receiving set and a case thereforhaving a built-in dynamic loud speaker with. voice. and field coils, asecond dynamic loud speaker with voice and field coils remote from saidreceiving set, a cable having conductors therein and extending betweensaid receiving set and said remote loud speaker, an antenna for saidreceiving set and comprising a conductor in said cable, a first circuitbetween said receiving set and said built-in loud speaker, a secondcircuit between'said receiving set and said remote loud. speaker andcomprising other conductors in said cable, a unitary switch forselectively impressing theoutput of said receiving set upon the voicecoils of said speakers by means. of said circuits, a third circuit forimpressing electrical energy upon the field coil of said: remote loudspeaker, arelay comprising a switch. in said third circuit for theclosing thereof, and electromagnetic means in said second circuit foractuating said relay switch, said electromagnetic means being energizedincident to. the impression of such output upon the voice coil of saidremote loud speaker.

4. A radio wave receiver comprising a local electrodynamic speakerincluding a voice coil and a field coil, an output thermionic tubeincluding a plate, and there being a source of electrical energy forsaid field coils and said tube, in combination with a remoteelectrodynamic speaker including a voice coil and a field coil, acircuit from said source of energy to the field coil of the remotespeaker, a relay adapted to close said circuit to energize said fieldcoil, a circuit from said source of energy for energizing the field coilof the local speaker, a switch for opening and closing the field circuitof the local speaker, and a circuit including a switch for connectingsaid plate to the voice coil of the local speaker or to the voice coilof the remote speaker, said relay being connected in circuit with theplate circuit leading to the voice coil of the remote speaker and beingenergized incident to the closing of said circuit, said switches beinginterlocked so that the circuit to the field 'coil of" they localspeaker is closed concurrently I with the closingof the circuitfromqthe. plate to the voice coil in' the local speaker; and the circuitto the field' coili of the local speaker is 0pened concurrently with theopening of the circuitto-the voice coil' of the local speaker and theclosing of the circuit to the voice coil of the remotespeaker'. I

5. A radio wavereceiver comprising two electrodynamic speakers, eachofsaid speakers com- T prising a voice coil and a field coil, one ofsaid speakers being housed with said-receiver and the other remotetherefrom, an output thermionic tube including aplate-in said receiver,there being a source of electrical energy-ion said tube, and a source ofenergy for the field coil of each of' said speakers, a circuit forconnecting the field coil'ofthe first ofsaid speakers to the said sourceof energy therefor and including a switch for the opening and closing ofsaidcircuit, a circuit leading from said source of energy for the fieldcoil of the second of said speakers and including a relay switch forclosing said circuit incident to energization ofsaid relay, a circuitfor connecting the voice coil of the first speaker L t'o'the-plateofsaid tube, a circuit -forconnecting the-voice coil of the second speakerto the plate of said tube, said circuit to the voice-coil of the secondspeaker including said relay for the actuation thereof when saidcircuit' is energized,

a switch for singly completing the circuits from said plate to the voicecoils of'the respective speakers, and means for interlocking saidseveral switches so that the first named switch is closed concurrentlywith the-manipulation of the second named switch for closing" thecircuit to the voice coil: of the first speaker, the first switch beingopened concurrently with manipulation of the" second named switch toopenthe circuit to the voice coil of the first speakerand toclose thecircuit to the voice coil of the-second speaker.

6. A radio receiver comprising an 'electrodynamic loud speaker includinga field coil and a voice coil, a thermionic output tube including aplate, there being a source of electrical energy for energizing saidfield coil, a circuit for connecting said-field coil to saidsourceofenergy, a switch'for opening and closingsaid circuit, a circuit forconnecting the voice coil of said speaker to said plate, a switclr foropening and closing the circuit connecting said plate and voice coil, acabinet for enclosingthe named parts of said receiver, a second cabinet,an electrodynamicspeaker in said second cabinet and including a fieldcoil and a voice coil, a multiple conductor cable extending between saidcabinets, there being a source of energy for the field coil of saidsecond speaker, a circuit for connect ing the field coil of the secondspeaker to the source of energy therefor and including a relay forclosing said circuit, conductors in said multiple conductor cable, thevoice coil of said second speaker, said relay, the secondly namedswitch, and the plate of said tube, said 'circuit being adapted to beopened and closed by said switch, the last named circuit when closedconducting energy to said relay and the voice coil of the secondspeaker, said switches being interlocked, the closing of the firstswitch being concurrent with the closing of the plate circuit to thevoice coil of the first speaker by said second switch.

'7. A radio receiver comprising an electrodynamic loud speakerhaving afield coil and a voice cell, a thermionic output tube including a plateand a filament, a source of electrical energy for energizing said fieldcoil, a circuit for connecting said field'coil to the source of energy,a switch for opening and closing said circuit, a circuit for connectingthe voice coil of said speaker to said plate, a switch for opening andclosing the circuit connecting said plate and voice coil, a cabinet forenclosing the named parts of said receiver, a second cabinet, anelectrodynamic speaker in said second cabinet, said speaker having afield coil and a voice coil, a multiple conductor cable, extendingbetween said cabinets, there being a source of energy for the field coilof said second speaker and for the filament of said tube, a circuithaving a leg for connecting the field coil of the second speaker to thesource of energy therefor and having a relay therein, for closing saidcircuit, said circuit leg including conductors in said cable, and acircuit for conducting energy from said plate to the voice coil of thesecond speaker and comprising other conductors in said cable, thesecondly named switch, and said relay, the last named circuit beingopened and closed by said secondly named switch, said relay beingenergized incidental to the passing of energy through the last namedcircuit, all of said switches being interlocked so that the closing ofthe first switch occurs coincidentally with the closing of the secondswitch to connect the voice coil of the first speaker to said plate, andthe opening of the first switch occurs coincidentally with themanipulation of the second switch to disconnect the voice coil of thefirst speaker from said plate and to. connect the voice coil of thesecond speaker.

8. A radio receiver unit comprising an electrodynamic speaker, a cabinetfor said unit and said speaker, a second speaker remote from saidreceiver, a cabinet for said second speaker, a multiple conductor cableextending between said unit and said second speaker, a first circuit forconducting energy to the receiver and comprising energy intake meansthrough said second cabinet and conductors in said cable, a secondcircuit for conducting energy to said second speaker, a relay comprisinga switch in said second circuit for the closing thereof, andelectromagnetic means for actuating said switch, and means forenergizing said electromagnetic means comprising a third circuitcomprising conductors in said cable and leading from said unit.

9. A radio receiver unit comprising an electrodynamic loud speaker andmeans for attaching an antenna, a cabinet for said receiver, anelectrodynamic speaker removed from said unit, a multiple conductorcable extending between said cabinet and said second speaker, a firstcircuit for conducting electrical energy to said receiver and includingconductors in said cable and energy intake means associated with saidsecond speaker, an antenna in said cable for engagement with saidantenna attaching means, a second circuit for conducting energy to saidsecond speaker, a relay comprising a switch in said second circuit forthe closing thereof, and electromagnetic means for actuating saidswitch, and means for energizing said electromagnetic means comprising athird circuit comprising conductors in said cable and leading from saidunit.

10. A radio receiving unit including an electrodynamic speaker, a voicecoil in said speaker, a field coil in said speaker, a thermionic outputtube including a plate, a circuit for conducting power to said fieldcoil, a second circuit for conducting power from said plate to the voicecoil of said speaker, a switch mechanism disposed in said circuits andadapted to open and close said circuits simultaneously, a cabinet forenclosing the unit and said speaker, a second cabinet removed from saidfirst named cabinet, a multiple conductor cable extending between saidcabinets, an electrodynamic speaker in said second cabinet and having afield coil and a voice coil, there being a source of energy for saidreceiver and for the field coil of the second speaker, a third circuitfor conducting power from said source of energy to said receiver andincluding conductors in said cable and energy receiving means at thesecond of said cabinets, a fourth circuit for conducting energy fromsaid source of energy to the field coil of the second speaker, a relayin said fourth circuit and adapted to close said fourth circuit, and afifth circuit for conducting energy from said plate to the voice coil ofthe second speaker through said switch mechanism, conductors in saidcable and said relay, said fifth circuit, when closed, conducting energyfrom said plate to cause energization of said relay, the said switchmechanism closing said fifth circuit subsequent to the opening of saidfirst and second circuits.

WILLIAM J. SCHNELL.

